Method of dephosphorizing ferrotungsten.



ATEN OFFIGE lumen, STATES rnmmmck M. amour, or NIAGARA FALLS, NEWxonxQhssmnon TO nnno'rno METALLURGICAL COMPANY, 01' NEW YORK, N. Y., AR-POBAT ION or wrzsr VIRGINIA.

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1,081,569, Io'Dnwing.

To all 'aqliom it'ntay comm, Z

Be it known that-I, 'Fnnnmio r Bncxn'r,

a subject of the Km of Great Britain, re-.

' tungsten-content .siding' at Niagara alls, in the county of Niagaraand fate of iNew= York, have invented certain new anduseful Improvements'in'! Methods of: hosphorizing Ferrotungsten, of which the tbllowing isa specification. I

I This invention relates to methods of dephosphori'zing ferrotungsten,particularly errotungstenv which by reason of its high brought tothethinly-fluid condition requisite for continuoustapping or pouring.

Y As is well known, commercial ferrotungsten containing 75-80- percent.or upward of tungsten'is diflicultly. fusible, and requires theapplication of extremely high tem' tures in order to bring it to a fluidcon ition or to melt it into a.homogeneous mass, The solidlfied alloy ishowever comparatively brittle, and can be easily ground turesufiiciently high to fuse or a bath. It is therefore desirable that thebath should consist.,'of an ore of the refractory metal which entersinto the constitution of the alloy, with such basic addition, usuallylime, as vmay be required.- Anillustrative example of my method is asfollows: Ferrotungsten, containing 7 580 per cut. of tungsten, iscrushed to pass a 10-12 mesh. screen,and is fed in a continuous streamto the surface of a molten bath consisting of scheelite and lime inapproxi mately e ual proportions. This bath is maintaine by the passagetheret-hrough of an electric current at such temperature will sufiice tofuse or at least to agglomerate I Specification of Letters Patent. huuua nan April 24, 1913. Serial Ho: 763,250.

cannot economically be' the -unti it becomes'sluggish in its refininaction, after which it is replaced by a resh bath. Duringthe operation"the phosphoruscontent of the bath gradually increases, and when ayoubath has been used as long as is advisable under the particularcircumstances, it'is tapped from the 1purified alloy. The bath'maybe'used Patented Dec, 16, 1913-,

furnace, permitted to cool, and ti'eated as a: high phosphorus ore oftungsten; that is to say, it may .be smelted with silicon or with carbonfor preparation. of a ferroalloy, which, being comparatively high inphosphorus, may be purified by any desired method, for example as abovedescribed, or by any of the methods described in my copendingapplication Ser. No. "728,498, filed October 29, 14112. It will ofcourse be un-,

derstood that the reduction of phosphorus in smelting the phosphoriaedbath is by no" means quantitative, so that itis often pra'c .ticable topurify the ferroalloy obtained by. smelting the rejected baths -bydephosp orization in fresh baths without involv ing any seriousaccumulation of phosphorus in the process. This is particularly the casewhen the ore employed for the fresh bath is substantially free fromphosphorus.

This method is chiefly applicable to the treatment of ferrotungstenwhich is low in carbon, inasmuch as a similar treatment of high-carbonferrot-ungsten is apt to entail a reduction of phosphorus from the'bath, particularly when the bath is relatively high in phosphorus, withthe result that the alloy is imperfectly dephosphorized. The ap-,

plicability of the method is independent of the tungsten-content of thealloy, and the method is directly applicable to the treatment ofproducts having a tungsten-content of 94- to 98 per cent, such forexample as the product known to the trade as tung- .sten powder; and the,term-ferrotungsten is herein used as including such products.

to the action. of an overlying bath of basic According to the presentmethod, the

li'errotungsten is brought-in solid form. into l rotungsten, whichconsists in bringing the in Letters PatntNo. 1,081,569.

presence of the basic bath, and undergoes progressive heating-in thebath, encountering during such heating the conditions which accomplishthe dephosphorizationu .1. The method of dephosphorizing fer--rotungstem which consists inbringing the fcrrotungsten in solid forminto presence of a molten basic' oxidizing bath.

2. The method of dephosphorizing ferferrotungsten' in solid form intopresence of a molten basic oxidizing bath maintained at a temperatureapproximating or above the fusing-point of the ferrotungsten.

3. The method of dephosphorizing fer- 1'otungsten,'Wl1icl1 consists inbringing the ferrotungstensolid form into presence} of a molten basicoxidizing bath containing an oxygen compound of tungsten.

4:. The' method of .dephosphorizing ferrotungsten, which; consists inbringing the ferrotungsten in solid form into presenceof a molten'basicoxidizing bath containing an oxygen compound of tungsten, saidbathmaintained at .a temperature approximating V or above thefusing-point,- of the ferro Witnesses"? tungsten. v

: 5. The method of' dephosphorizing ferion [smLJ 0 r rect rotungsten,which consists in feeding solid fe'rrotungstenin subdivided form to thesur-" face of a molten basic oxidizing bath.

6; The method of -dephosphorizing ferrotungsten, which consists infeeding solid ferrotungsten in subdivided form to the surface of amolten basic oxidizing'bat-h maintained at a temperature approximatingor above the fusing-point of the ferro- I tungsten.

7. The method of dephosphorizing ferrotungsten, which'consists infeeding solid \ferrotungsten in subdivided form to, the surrotungsten,which consists in feeding solid ferrotungsten in subdivided form to thesurface of. a moltenbasic oxidizing bath conface. of a molten basicoxidizing bath containing an oxygen compound of tungsten, saidbathmaintained at a temperature approximating "or above the fusing-pointof the ferrotungsten. 3

' In -'testimony whereof I afiix'my signature in presencemf twowitnesses.

C. P. Townsnnp, E. DANIELS.

It hereby certified that in Letters Patent No. 1 )8 l,569, grantedDecember 16, r 1913, upon the application :of Frederic M. Becket,,ofNiagara. Falls, New York, o an improvemen i Methods of Dephos phorizingFerrot ungstenz an error appears in printed specification reduiringcorrection as. follows: Page 1 lines 32 33, for theword depolarized readdeplwiyalzoried; and that: thesaidLetters Patent should be read withthis correctiontherein that the same may-conform the record of thecasein the Patent Office. I I i i Signed and sealed this 2 0th day of April,D.,191 5;

I J. T. NEWTON, Acid/11g Commissioner of Patents;

' FREDERICK M; BEOKET,

